This invention relates generally to apparatus for collecting data from several inputs and more particularly, but not by way of limitation, to microcomputer-based apparatus for receiving inputs to be transferred to another microcomputer-based device in monitoring the operation of a railroad train.
For purposes of safe and efficient operation of a railroad train, it is important that the train engineer know the manner in which the train is moving. To known the manner in which the train is moving, the engineer must know the speed at which the train is moving, the rate at which the speed is changing (i.e., the acceleration or deceleration), and the distance which the train has moved from a selected location.
The engineer must, of course, known the present speed of the train to insure that it is being maintained within safe and legal limits.
Knowledge of the acceleration/deceleration is also important because it enables the engineer to know the speed toward which the train is changing and the rate at which the change is occurring. Because the engineer cannot physically detect, or "feel," slight changes in speed of the train, the engineer needs some device which tells him the acceleration (i.e., rate of speed increase) or deceleration (i.e., rate of speed decrease). For example, when a train crests a hill, the engineer should try to maintain a zero rate of speed change to prevent the train from running away and to minimize forces on its descent.
To enable the engineer to known when the end of the train has passed a certain point, such as a railroad crossing, it is also important for the engineer to have information regarding the distance which the train has traveled. This is especially important today because of the trend toward eliminating cabooses (and the personnel located therein) from trains. Without personnel located at the end of the train or some other means for advising the engineer of the exact location of the end of the train, the engineer will not be able to accurately determine where the end of the train is relative to the surrounding terrain.
We are aware that various means for indicating the speed of a train have been proposed and/or developed. These speedometers have generally been of either the electro-mechanical or the mechanical type. The electro-mechanical types are analog devices which operate off a signal generated by an axle alternator transducer. The mechanical types are similar to speedometers found in automobiles.
Although these prior devices may be functional, they do have shortcomings. Prior analog devices have needle meters which indicate the speed; however, the needles of such meters oscillate, thereby preventing accurate readings of the speed. Such analog types also have calibration problems arising from the shocks and vibrations inherent in a moving railroad train. These prior types of speedometers also fail to detect slow speeds such as those below three miles per hour. This is an important shortcoming in several situations, such as during a coal loading operation where the train moves slowly as it is being filled with coal. These prior devices also do not detect and compensate when wheel slippage between the wheels of the train and the track occurs. These prior devices also do not simultaneously indicate the acceleration/deceleration and the distance traveled.
Besides being important to apprise the engineer of the real time speed, acceleration/deceleration and distance traveled of the train, it is important to maintain a continuous record of such data so that management and maintenance personnel can properly assess the manner in which the train has been operating. This need has been recognized and attempts have been made to meet it. Mechanical recorders utilizing disks which rotate in correspondence with train movement and which are inscribed by an implement moved by a mechanical speedometer are known. Strip chart recorders are also known. Information on the train operation has also been stored on magnetic tape and in electronic memory, such as random access memory. These storage media have such limitations as limited storage space, limited retention times without adequate backup power supplies, and extended transfer times in copying the data from one storage device to another.
The foregoing needs have been met and the above-noted and other shortcomings of the aforementioned prior art have been overcome by an apparatus for monitoring motion of a railroad train described in U.S. Pat. No. 4,561,057 issued Dec. 24, 1985. Although this previously used and patented invention does meet these needs and overcome these shortcomings, an additional need has arisen. This need is for an ability to collect a plurality of external data inputs in a manner which is compatible and useful with the invention of U.S. Pat. No. 4,561,057. That is, such data collection need further requires that external inputs be separately received and processed and then interfaced into the previously patented invention. Examples of such external data to be obtained on a railroad train are changes in the signals from the train line or from transducers monitoring pressure in the brake pipe, the brake cylinder and the equalizer reservoir. Other examples include detecting bell and horn usage via pressure switches. Therefore, there is the further need for a suitable data collection apparatus.
It is preferable that such a data collection apparatus be separate from the components of the invention described in U.S. Pat. No. 4,561,057 so that the previously patented invention need not be substantially modified other than to include the interfacing capability for communicating with the data collection apparatus. Being separate necessitates a suitable housing for the data collection apparatus, which housing is preferably water-tight, easily mountable within the locomotive of a train and connectible to the train line and other sources of external data and to the components of the previously patented invention. Such a housing should also provide easy access to the internal electronic components so that they can be removed from the remainder of the housing for maintenance purposes or for utilization away from the train.
To facilitate the use of the data collection apparatus on a train, the apparatus should include suitable power conversion means for converting the nominal 72-volt power commonly found on a train to appropriate lower voltage levels compatible with the electronic components of which the apparatus is constructed. Such a power conversion means should incorporate a power failure detection circuit to insure that the apparatus commences operation in a suitable determinate operating state.
To enhance the flexibility of such an apparatus, it should include means which can be externally controlled to adapt the operation of the apparatus to a desired operating mode. This can be by a controllable binary counter which provides externally selectable timing signals.
So that the data collection apparatus can communicate with the previously known components described in U.S. Pat. No. 4,561,057, there is the further need for a suitable interface mounted in the previous invention and connectible to the data collection apparatus for interfacing the information obtained by the data collection apparatus to the previously patented railroad train motion monitoring apparatus. To enhance the operation of this railroad train motion monitoring apparatus, there is also the need for a suitable power failure detect circuit for detecting brownouts or other power failures occurring when a locomotive is started so that the electronics of the previously patented apparatus are reset to a suitable determinate state.